1 files changed, 105 insertions, 0 deletions
diff --git a/plumbing/object/commitgraph/commitnode_walker_ctime.go b/plumbing/object/commitgraph/commitnode_walker_ctime.go
new file mode 100644
index 0000000..f6a1b6a
--- /dev/null
+++ b/plumbing/object/commitgraph/commitnode_walker_ctime.go
@@ -0,0 +1,105 @@
+package commitgraph
+
+import (
+	"io"
+
+	"github.com/emirpasic/gods/trees/binaryheap"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+)
+
+type commitNodeIteratorByCTime struct {
+	heap         *binaryheap.Heap
+	seenExternal map[plumbing.Hash]bool
+	seen         map[plumbing.Hash]bool
+}
+
+// NewCommitNodeIterCTime returns a CommitNodeIter that walks the commit history,
+// starting at the given commit and visiting its parents while preserving Committer Time order.
+// this appears to be the closest order to `git log`
+// The given callback will be called for each visited commit. Each commit will
+// be visited only once. If the callback returns an error, walking will stop
+// and will return the error. Other errors might be returned if the history
+// cannot be traversed (e.g. missing objects). Ignore allows to skip some
+// commits from being iterated.
+func NewCommitNodeIterCTime(
+	c CommitNode,
+	seenExternal map[plumbing.Hash]bool,
+	ignore []plumbing.Hash,
+) CommitNodeIter {
+	seen := make(map[plumbing.Hash]bool)
+	for _, h := range ignore {
+		seen[h] = true
+	}
+
+	heap := binaryheap.NewWith(func(a, b interface{}) int {
+		if a.(CommitNode).CommitTime().Before(b.(CommitNode).CommitTime()) {
+			return 1
+		}
+		return -1
+	})
+
+	heap.Push(c)
+
+	return &commitNodeIteratorByCTime{
+		heap:         heap,
+		seenExternal: seenExternal,
+		seen:         seen,
+	}
+}
+
+func (w *commitNodeIteratorByCTime) Next() (CommitNode, error) {
+	var c CommitNode
+	for {
+		cIn, ok := w.heap.Pop()
+		if !ok {
+			return nil, io.EOF
+		}
+		c = cIn.(CommitNode)
+		cID := c.ID()
+
+		if w.seen[cID] || w.seenExternal[cID] {
+			continue
+		}
+
+		w.seen[cID] = true
+
+		for i, h := range c.ParentHashes() {
+			if w.seen[h] || w.seenExternal[h] {
+				continue
+			}
+			pc, err := c.ParentNode(i)
+			if err != nil {
+				return nil, err
+			}
+			w.heap.Push(pc)
+		}
+
+		return c, nil
+	}
+}
+
+func (w *commitNodeIteratorByCTime) ForEach(cb func(CommitNode) error) error {
+	for {
+		c, err := w.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		err = cb(c)
+		if err == storer.ErrStop {
+			break
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (w *commitNodeIteratorByCTime) Close() {}